“This was part of ongoing research companies do to test different products, and that was what it was; it was poorly communicated,” Sandberg, Facebook’s chief operating officer, said while in New Delhi. “And for that communication we apologize. We never meant to upset you.”

Sandberg was in India meeting with smaller-sized businesses that advertise on Facebook. The company is working with advertisers outside the U.S. to launch campaigns that are more tailored to local markets. She was meeting with entrepreneurs and businesswomen as part of her “Lean In” campaign when she commented on the study.

The uproar centered on Facebook’s one-week experiment in 2012, in which the company’s data scientists enabled an algorithm to determine whether lowering the number of positive or negative posts in users’ news feeds could prompt them to post more positive or negative content.

The research, published in the March issue of the Proceedings of National Academy of Sciences, sparked soul-searching and questions among researchers and ethicists over the social network’s ability to tweak its users’ emotions.

“We take privacy and security at Facebook really seriously because that is something that allows people to share” opinions and emotions, Sandberg said.